Interval optimal scheduling of hydro-PV-wind hybrid system considering firm generation coordination

Coordination of hydropower with multiple renewable sources can effectively reduce the adverse effects of large-scale renewable energy integration in power systems. A yearly scheduling model was proposed for a hydro-photovoltaic (PV)-wind hybrid system, maximising its generation interval and considering firm generation limits. Firm generation ensures reliable monthly generation and reduces generation fluctuations. Because the probability distributions of wind power, water inflow and solar radiation are difficult to predict precisely, interval optimisation is employed to solve this problem by considering only the possible intervals of random variables. It reduces errors introduced by distribution assumptions, acquires possible generation intervals and reduces computation burden. To handle the scheduling model using intervals, a pessimistic preference ordering of interval numbers is employed. The proposed interval optimal scheduling model is illustrated and analysed for a realistic case study in Yunnan.